Pen needles are designed to be attached to a medication pen and are especially useful for delivering self-administered injectable medications, such as insulin. Medication pens and associated pen needles are disclosed in U.S. Pat. No. 7,645,264, and in U.S. Patent Application Publication Nos. 2009/0069755 and 2012/0022460, all of which are incorporated herein by reference in their entirety for their teachings of pen needle design and construction.
In one well-known commercial pen needle device, a needle-bearing hub is provided inside a funnel-shaped, outer plastic cover. The needle (cannula) is affixed in an axial bore of the hub with one end (the “injection end”) protruding from the distal or “patient side” of the hub and covered by a removable inner cover, and the other end (the “non-injection end”) recessed in a cavity on the proximal or “non-patient” side of the hub, which is adapted for attachment to a medication pen. The hub and the injection end are received in the outer cover, where the hub is secured in position by ribs, and a closure in the form of a paper and foil “teardrop” label is heat-sealed on the edge or flange of the open end of the cover. The user removes the label and holds the outer cover to install the hub, typically threading the hub onto the medication pen. Once the hub is installed on the pen, the outer cover can be removed by pulling it distally off the hub. The inner cover is then removed from the injection end of the needle to allow an injection to be made.
Current pen needle labels have a plastic layer on the underside and are fastened to the flange of a pen needle outer cover using heat to melt the plastic layer to the plastic flange. The heating and its associated dwell time are critical, and must be maintained through hundreds of thousands of sealing repetitions per day. In large-scale pen needle manufacturing, this heat seal step may become a bottleneck or rate-limiting step. Therefore, one object of the invention is to provide a closure for a pen needle outer cover that does not require a heat-sealing step to attach it to the outer cover, while retaining all the sterility and ease-of-use functionality of current products.
Current pen needle labels may also be subject to delamination in some regions and under certain conditions where the labels are exposed to high levels of humidity, or if the packaging gets wet. Delamination can render the pen needle unusable by leaving the plastic bottom layer of the label intact across the outer cover opening while the outer layers of the label delaminate when the patient tries to remove the label to access the needle. Therefore, another object of the invention is to avoid the drawbacks associated with delamination of a peel-type label for a pen needle.
A further problem addressed by the invention relates to providing evidence of tampering when a pen needle has been opened. Current pen needle labels can be reattached to the outer cover flange by reheating the plastic underlayer of the label and pressing it against the outer cover flange, or by using adhesives. The pen needle label can be made to look as though it is intact even though the sterility barrier has been compromised. Thus, another object of the invention is to provide a tamper-evident closure and labeling system.
Current pen needle labels are generally peeled completely off the outer cover flange, which leaves the user with a loose piece to discard. Some pen needle users peel the label off only partially along its sealed area, leaving a small portion of the label attached to the outer cover flange. This pattern of use makes it difficult to install the pen needle on a medication pen, as it requires the pen to be inserted into the pen needle cover at an angle to access the needle-bearing hub while avoiding the hanging label, which could get caught between the threads of the medication pen and the needle hub. Thus, another object of the invention is to provide a pen needle closure that allows the user to leave a user-separable portion of the closure attached to the outer cover while leaving an unobstructed opening for installation of the pen-needle on a medication pen.